Field of the Invention
The invention relates to a contact force sensor for use in an ablation catheter, etc.
Description of Related Art
It is known that an ablation treatment is to percutaneously insert a catheter into a target site in the heart and apply a high frequency current through an electrode disposed on the tip of the catheter to selectively cauterize the abnormal site, so as to treat atrial arrhythmia, etc.
The ablation treatment cures arrhythmia by cauterizing a conduction path of an abnormal electrical signal that causes arrhythmia in the heart to block the conduction path.
To perform the ablation treatment, an ablation catheter is used, in which an electrode that allows passage of high frequency electricity is disposed on the tip of the ablation catheter for cauterizing the conduction path of the abnormal electrical signal in the heart (see Patent Literature 1, for example).
During the ablation treatment that uses such an ablation catheter, the electrode of the ablation catheter is placed in contact with the abnormal site on the inner wall of the heart and then a high frequency current is applied to cauterize the abnormal site.
However, if the contact force the electrode applies on the abnormal site on the inner wall of the heart is not strong enough, the abnormal electrical conduction path may not be cauterized sufficiently; on the other hand, an excessive contact force may penetrate the inner wall of the heart and cause a complication, such as cardiac tamponade.
For this reason, a catheter with a contact force sensor for sensing the contact force of the electrode on the tip has been proposed (see Patent Literature 2).